According to the experiments, amylase activity is highest at which pH value among those tested?

• A. pH 5
• B. pH 3
• C. pH 11
• D. pH 7

Answer: (D)

Enzyme activity depends on pH because pH influences the ionization of amino acids in the active site and the substrate, which shapes the enzyme’s shape and how well it can catalyze a reaction. Amylase works best at a near-neutral pH, where the catalytic residues are correctly charged and the starch substrate binds effectively. At very acidic (like 3 or 5) or very basic (like 11) pH values, the enzyme’s active site is disrupted and substrate interaction is less favorable, so activity drops. Among the tested values, neutral pH 7 provides the conditions that best support amylase function, giving the highest activity.